DRW: Fix signed/unsigned mismatches in shader code

Fix the following error messages on Blender startup
since commit 308a12ac64.

This commit fixes T98194.

Reviewed By: fclem
Differential Revision: https://developer.blender.org/D15007

source/blender/draw/engines/overlay/overlay_shader_shared.h

@@ -24,19 +24,19 @@ typedef struct OVERLAY_GridData OVERLAY_GridData;
 #define BG_MASK 5
 
 enum OVERLAY_GridBits {
-  SHOW_AXIS_X = (1 << 0),
-  SHOW_AXIS_Y = (1 << 1),
-  SHOW_AXIS_Z = (1 << 2),
-  SHOW_GRID = (1 << 3),
-  PLANE_XY = (1 << 4),
-  PLANE_XZ = (1 << 5),
-  PLANE_YZ = (1 << 6),
-  CLIP_ZPOS = (1 << 7),
-  CLIP_ZNEG = (1 << 8),
-  GRID_BACK = (1 << 9),
-  GRID_CAMERA = (1 << 10),
-  PLANE_IMAGE = (1 << 11),
-  CUSTOM_GRID = (1 << 12),
+  SHOW_AXIS_X = (1u << 0u),
+  SHOW_AXIS_Y = (1u << 1u),
+  SHOW_AXIS_Z = (1u << 2u),
+  SHOW_GRID = (1u << 3u),
+  PLANE_XY = (1u << 4u),
+  PLANE_XZ = (1u << 5u),
+  PLANE_YZ = (1u << 6u),
+  CLIP_ZPOS = (1u << 7u),
+  CLIP_ZNEG = (1u << 8u),
+  GRID_BACK = (1u << 9u),
+  GRID_CAMERA = (1u << 10u),
+  PLANE_IMAGE = (1u << 11u),
+  CUSTOM_GRID = (1u << 12u),
 };
 
 /* Match: #SI_GRID_STEPS_LEN */

source/blender/draw/intern/shaders/common_gpencil_lib.glsl

@@ -393,7 +393,7 @@ vec4 gpencil_vertex(ivec4 ma,
                         col2,
                         fcol1,
                         viewport_size,
-                        0,
+                        0u,
                         vec2(1.0, 0.0),
                         out_P,
                         out_N,

source/blender/draw/intern/shaders/common_math_lib.glsl

@@ -110,6 +110,7 @@ float len_squared(vec3 a) { return dot(a, a); }
 float len_squared(vec2 a) { return dot(a, a); }
 
 bool flag_test(uint flag, uint val) { return (flag & val) != 0u; }
+bool flag_test(int flag, uint val) { return flag_test(uint(flag), val); }
 bool flag_test(int flag, int val) { return (flag & val) != 0; }
 
 void set_flag_from_test(inout uint value, bool test, uint flag) { if (test) { value |= flag; } else { value &= ~flag; } }